Apple Computer on Tuesday unveiled a 13-inch MacBook, the newest member of its family of Intel-based laptops.

Billed as a replacement to both the iBook and the 12-inch PowerBook, the , which is on sale now, starts at $1,099 for a 1.83GHz Intel Core Duo processor with a 60GB hard drive. Like the former iBooks, that model--and the next model up, which packs a 2.0GHz processor, a 60GB hard drive and a $1,299 price tag--is cased in white.

The top-of-the-line 2.0GHz model, starting at $1,499, comes equipped with an 80GB hard drive and is available only in black.

The new MacBooks weigh 5.2 pounds each and measure about 1 inch thick, making them about 20 percent thinner than the iBook. According to press materials from Apple, they're also equipped with a display that is 79 percent brighter than the iBook and the 12-inch PowerBook.

Each of the new MacBooks will come with a built-in iSight video camera, which can be used for video conferencing and video podcasts.

Apple first announced the MacBook Pro series, which features models with 15-inch and 17-inch screens, in January. It also offered a speed bump to the 15-inch MacBook Pro, with the $1,999 model now sporting a 2GHz chip, up from 1.83GHz and the $2,499 model now running at 2.16GHz, up from 2 GHz. The 15-inch and 17-inch MacBook Pros can also now be outfitted with a glossy, widescreen display for no added charge via the configure-to-order option on Apple's online store.

Rumors of the latest MacBook revelations had been swirling in recent weeks, with one Mac rumor site would be a week earlier.

Samir Bhavnani, an analyst at Current Analysis said that the new MacBook should help Apple in the back-to-school season, which accounts for roughly one-fifth of overall U.S. retail sales of PCs and printers.

"Apple will pose a threat for the first time in years to traditional 'back to school' leaders such as HP and Toshiba," Bhavnani said.

JP Morgan analyst Bill Shope said that the fact that the notebooks are available now should help Apple with its sales to schools as well. Shope added that, with the iBook, Apple is now about 90 percent done with its Intel chip transition, needing only to update its professional desktop.

"The low-volume Power Mac is the only product that remains to be introduced and we expect this to occur late in the summer," Shope wrote in a research note.